Low dissolved oxygen concentrations that occur in many bodies of water when nutrients stimulate the growth of algae that subsequently die and are decomposed by oxygen-using bacteria.
Answer:
Russia and Brazil have the largest area of boreal forests but Russia has the most area out all countries.
Explanation:
<h2>Answer: Option D</h2><h2 />
Option A, "a large swirling, low-pressure system that forms over the warm Atlantic Ocean" is incorrect because tornadoes do not form over water. That would be a hurricane.
Option B, "a winter storm with wind speeds of at least 56 km/h and low visibility" Is incorrect because tornadoes do not form in cold weather. That would be a blizzard.
Oa boundary between two air masses of different density, moisture, or temperatureption C, "a violently rotating column of air in contact with the ground" is correct <u>because tornadoes are columns of air that rotate due to warm air and cold air colliding.</u> They usually occur during a thunderstorm.
Option D, "a boundary between two air masses of different density, moisture, or temperature" is incorrect because tornadoes are not based on air mass, density, moisture, or temperature. This would be a front.
